Grouchy at 10 P.M. of the 17th issues his orders for the next day to move on Sart-à-Walhain at 6 and 8 A.M. 250 But at daybreak he has learned that the Prussians had retired on Brussels 251 Yet he does not change his orders 252 He should have marched for the bridge of Moustier at daybreak 253 Opinion of Jomini 253 Opinion of Clausewitz 253 Opinion of Charras 253 Grouchy neglects to reconnoitre to his left 254 He arrives at Walhain and stops at the house of M. Hollert, a notary 255 He writes a despatch to the Emperor 255 Analysis of this despatch 255, 256 The sound of the cannon of Waterloo is heard 256 Grouchy’s plain duty 256 Gérard’s advice 256 Grouchy refuses to follow it 257 And resumes his march on Wavre 257 Condition of the roads and bridges 258 Grouchy might have crossed the Dyle after having arrived at La Baraque 259 Three general misconceptions 259 1. As to the place where the sound of the cannon was heard 259 2. As to the necessity of marching by way of Mont St. Guibert 259 3. As to the resistance to be expected at the bridges 260 Grouchy might have been across by 4 P.M. 260 Positions of the IVth and IId Prussian Corps at that moment 261 And of the Ist Corps 261 Probability that Grouchy would have arrested the march of Bülow and Pirch I. 261 Zieten’s march, however, would not have been interfered with 261 Bülow reaches St. Lambert at noon 262 Pirch I. and Zieten do not leave Wavre till nearly noon 262 Tardiness of these movements 263 Accounted for by Gneisenau’s distrust of Wellington 263 His postscript to the letter to Müffling 263 His doubts as to Wellington’s accepting battle dispelled by the sound of the cannon of Waterloo 264 The combat at Wavre 264, 265